A baseball diamond is actually a square. The names of three other quadralaterals also describe the figure.
Any four-sided polygon is a quadrilateral. Quadrilaterals that have certain properties are called special quadrilaterals.
A trapezoid is a quadrilateral with one and only one pair of parallel sides.
A parallelogram is a quadrilateral with two pairs of parallel sides.
A rhombus is a quadrilateral with four congruent sides.
A rectangle is a quadrilateral with four right angles.
A square is a quadrilateral with four congruent sides.
A TRIANGLE is a 3-sided figure.
A CIRCLE is not a polygon.
A PENTAGON is a 5-sided figure.
A HEXAGON is a 6-sided figure.
A HEPTAGON is a 7-sided figure.
An OCTAGON is an 8-sided figure.
A NONAGON is a 9-sided figure.
A DECAGON is a 10-sided figure.
A SQUARE can be a RECTANGLE, but a RECTANGLE cannot be a SQUARE.
Is it a POLYGON or not?
Polygon
(straight sides)
Not a Polygon
(has a curve)
Not a Polygon
(open, not closed)
Simple or Complex POLYGON
A simple polygon has only one boundary, and it doesn't cross over itself.
A complex polygon intersects itself.
Simple Polygon
(this one's a Pentagon)
Complex Polygon
(also a Pentagon)
A convex polygon has no angles pointing inwards. More precisely, no internal angles can be more than 180°. Convex
If there are any internal angles greater than 180° then it is concave. (Think: concave has a "cave" in it) Concave
Regular or Irregular
If all angles are equal and all sides are equal, then it is regular, otherwise it is irregular
Any four-sided polygon is a quadrilateral. Quadrilaterals that have certain properties are called special quadrilaterals.
A trapezoid is a quadrilateral with one and only one pair of parallel sides.
A parallelogram is a quadrilateral with two pairs of parallel sides.
A rhombus is a quadrilateral with four congruent sides.
A rectangle is a quadrilateral with four right angles.
A square is a quadrilateral with four congruent sides.
A TRIANGLE is a 3-sided figure.
A CIRCLE is not a polygon.
A PENTAGON is a 5-sided figure.
A HEXAGON is a 6-sided figure.
A HEPTAGON is a 7-sided figure.
An OCTAGON is an 8-sided figure.
A NONAGON is a 9-sided figure.
A DECAGON is a 10-sided figure.
A SQUARE can be a RECTANGLE, but a RECTANGLE cannot be a SQUARE.
Is it a POLYGON or not?
Polygon
(straight sides)
Not a Polygon
(has a curve)
Not a Polygon
(open, not closed)
Simple or Complex POLYGON
A simple polygon has only one boundary, and it doesn't cross over itself.
A complex polygon intersects itself.
Simple Polygon
(this one's a Pentagon)
Complex Polygon
(also a Pentagon)
A convex polygon has no angles pointing inwards. More precisely, no internal angles can be more than 180°.
If there are any internal angles greater than 180° then it is concave. (Think: concave has a "cave" in it)
Regular or Irregular
If all angles are equal and all sides are equal, then it is regular, otherwise it is irregularMore Examples
(a "star polygon")